Developing device

Abstract

A developing device includes a rotatable developer carrying member enclosing a magnetic field generating portion including a plurality of magnetic poles and configured to carry a developer; and a resinous regulating portion provided at a position opposing the developer carrying member and configured to regulate an amount of the developer carried by the developer carrying member. The regulating portion is formed of a resin material containing magnetic powder, and at least a free end portion, opposed to the developer carrying member, of the regulating portion has relative permeability of 10 or more and 60 or less.

What is claimed is: 
     
       1. A developing device comprising:
 a rotatable developer carrying member enclosing a magnetic field generating portion including a plurality of magnetic poles and configured to carry a developer; and 
 a resinous regulating portion provided at a position opposing said developer carrying member and configured to regulate an amount of the developer carried by said developer carrying member, 
 wherein said regulating portion is formed of a resin material containing magnetic powder, and at least a free end portion, opposed to said developer carrying member, of said regulating portion has relative permeability of 10 or more and 60 or less. 
 
     
     
       2. A developing device according to  claim 1 , wherein said regulating portion is a plate-shaped regulating member. 
     
     
       3. A developing device according to  claim 1 , further comprising a developer accommodating container configured to support said developer carrying member,
 wherein said regulating portion is integrally molded with said developer accommodating container. 
 
     
     
       4. A developing device according to  claim 1 , wherein a portion of said regulating portion, in a range of not less than 1/10 of a magnetic field on an outer peripheral surface of said developer carrying member opposing the magnetic pole closest to said regulating portion, is formed of a resin material containing the magnetic powder. 
     
     
       5. A developing device according to  claim 1 , wherein the relative permeability is not less than 7.8×10 −3 ×(r 2 /M) where a magnetic field strength on the outer peripheral surface of said developer carrying member opposing the magnetic pole closest to said regulating portion is M (mT), and a distance between the outer peripheral surface and said regulating portion is r (μm). 
     
     
       6. A developing device according to  claim 1 , wherein at least the free end portion of said regulating portion has relative permeability of 20 or more.